It is a common medical practice to deliver medication to a patient by direct delivery of that medication into a blood vessel. Typically, intravenous delivery of the medication is employed when it is desired to deliver the medication systemically, that is, throughout the patient's body. When delivered intravenously, the medication returns through the venous system to the heart from which it is then pumped throughout the patient's arterial system to all parts of the patient's body. When it is desired to deliver medication to a specific, targeted organ, or to another localized portion of the patient's anatomy, the medication may be delivered into a specific artery leading to that organ or region. Medicine delivered through an artery is transported only to the organ or region to which the artery leads and not throughout the body. For example, it is a common practice when treating a malignancy of the liver with chemotherapy to deliver the medication through a catheter inserted into the hepatic artery which leads directly to the liver. The catheter may be connected to a subcutaneous port that is accessible by needle puncture through the skin or may be implanted in a manner such that its proximal end protrudes through the patient's skin for direct connection to a syringe or other medication injection device.
Delivery of medication through a patient's arteries presents considerations not present in venous delivery. For example, the blood pressure in the arterial system is considerably higher than in the venous system. Consequently, catheters used to deliver medication to an artery typically must have a thicker wall to reduce the chance of the catheter rupturing under the influence of the increased arterial pressure. Additionally, arterial blood has an increased tendency for retrograde flow into the catheter leading to thrombotic occlusion. Because of the increased blood pressure in the arterial system, it is important that the outlet of the catheter have a valve arrangement to prevent backflow of blood into the catheter.
Still another factor that must be considered is the manner in which the catheter will be held in place in the arterial system. It is important that the catheter be securely held so that it does not shift about to different positions. Such shifting could result in the catheter partially obstructing blood flow through the artery which would tend to create turbulence and increase the risk of clotting. Typically, such catheters are placed in a branch artery leading to the artery to which the medication is to be delivered. Thus, the outlet of the catheter is located at the juncture of the catheterized artery and the artery to which the medication is to be delivered. If the catheter is permitted to shift its position longitudinally in the branch artery, its outlet tip may project excessively into the artery to be medicated, partially obstructing that artery and increasing turbulence.
It would be desirable and there is a need to provide a valved catheter for arterial delivery of medication that reduces the tendency to clot and which effectively achieves the foregoing and other objectives.